In the conventional type of concrete hog slats (i.e., slender forms of trapezoidal cross-section), reinforcing bars may be provided at the top and bottom. The bottom reinforcing bar is initially supported within the casting form for the slat by suitable means so as to hold the bar in position and the top bar is hand placed after pouring of the concrete into the form. Centering of the bars is accomplished by eye and usually is inaccurate by virtue of the lack of lateral restraint. Additionally, it is very difficult to place the top bar accurately at a given position in the concrete.